Incandescent filament lamps

ABSTRACT

An incandescent filament lamp having an envelope closed with a wedge-shaped pinch seal and a cap disposed about the seal. Cuts are made in the cap and portions thus freed are bent inwards to provide a seating structure for the seal.

United States Patent Wright, deceased et al.

Aug. 5, 1975 INCANDESCENT FILAMENT LAMPS Inventors: John WilloughbyThomas Wright,

deceased, late of Leicester. England; by Audrey Mabel Wright. legalexecutor: by Denis Wilfred Clarke legal executor. both of Leicester.England Assignee: Thorn Electrical Industries Limited,

London, England Filed: Apr. 8, 1974 App]. No.: 458,976

Related U.S. Application Data Continuation of Ser. No. 827,497, May 231969. abandoned.

US. Cl. 313/318; 339/144 R Int. Cl. HOlj 5/48 Field of Search 313/317,318; 339/144 R,

339/144 T. 145 R145 D, 145 T, 146

[56] References Cited UNITED STATES PATENTS 3,327.28} 6/1967 Anderson etal. 313/3111 x 3.573.534 4/1971 Leighton 31 3111 FOREIGN PATENTS ORAPPLICATIONS 688.491 3/1933 United Kingdom 33 1/144 R Primaryl;'.\un1incrPaul A. Sacher AUG/710), Agent, or Firn1-R0bert F. OConnell[57] ABSTRACT An incandescent filament lamp having an envelope closedwith a wedge-shaped pinch seal and a cap disposed about the seal. Cutsare made in the cap and portions thus freed are bent inwards to providea seating structure for the seal.

5 Claims, 3 Drawing Figures 1 INCANDESCENT FILAMENT LAMPS This is acontinuation ofapplication Ser. No. 827,497, filed May 23, 1969, nowabandoned.

The present invention relates to the provision of cap connectors for thepinch sealed envelopes'of lamps, such as, for example, fluorescentlamps, discharge lamps and incandescent filament lamps.

It has been proposed that lamp envelopes should be closed with a pinchseal through which terminal leads for connections to filaments orelectrodes would be sealed. Such a pinch seal could be plugged directlyinto a socket thus dispensing with the need to seal a conductive caponto the end of the envelope. However, the introduction of such a lampwould require replacement of all existing sockets by sockets adapted toreceive pinch sealed lamps. This amount of obsolescence would not beacceptable in, for example, the field of domestic lighting, where itwould involve the replacement of many millions of light fittings. It ishowever clear that considerable manufacturing advantages could beobtained if lamps were pinch sealed.

According to the present invention there is provided a lamp having anenvelope closed by a pinch seal through which terminal leads for thelamp extend and a cap within which are provided one or more seatingstructures cooperating with the pinch seal to seat the envelope in thecap, portions of the terminal leads extending beyond the envelope beingsecured to the cap so as to prevent the envelope from moving axiallyrelative to the cap.

In a preferred form of the invention an incandescent filament lampincludes an envelope formed with a wedge-shaped pressed pinch seal, thethin end of the seal being the end remote from the filament. and a capwithin which are disposed one or more seating structures whichco-operate with the sides of the wedgeshaped seal to seat the envelopein the cap.

Advantageously, the pinch seal tapers on one or both sides from itscentre portion towards one or both of its edges.

The seating structure may include portions ofa shape complementary tothe shape of the seal whereby a face to face contact between the sealand the seating structure is maintained when the envelope is seated inthe cap.

The seating structures may be constituted by internally extending lugsformed by making cuts in the cap and bending inwards the section of thecap thus freed.

.Embodiments of the invention will now be described, by way of examplewith reference to the accompanying drawings, in which:

FIG. 1 is an exploded view of a first embodiment of the inventionshowing the cap and the envelope,

FIG. 2 is a side elevation in part section of a second embodiment,

FIG. 3 is a plan along III-III in FIG. 2,

In FIG. 1 of the drawings, a glass envelope 11 has a bulbous portion 12and a tapering portion 13. The tapering portion 13 has a wedge-shapedpressed pinch seal 14. Two leads 15 for the filament 16 of the lampextend through the closed end of the seal 14. A cap 17 in which theenvelope is seated has a base 18 and a side-wall 19, two pairs of lugs21, 22 and 23, 24 respectively securing the envelope 11 in position inthe cap 17. Each lug 21, 22, 23 and 24 is formed by making a V-shapedcut in the side wall 19 and bending the freed '2 section inwardly alongthe linejoining the ends of the arms of the V-shaped out;

The lugs 21,22 and 23, 24 thus form seatings that cooperate with thesides of the pinch seal 14 of the envelope II. The lugs of each pair 21,22 and 23, 24 are closer together at their ends nearer the closed end ofthe cap 17.

The lead wires 15 pass through holes (not shown) in the base 18 of thecap 17, and are soldered or welded to the cap 17. The lugs 21 to 24prevent rotational movement of the envelope and axial movement isprevented by the securing of the lead wires 15 to the cap 17.

The above example relates to one shape of lugs. It is clear that otherconfigurations of the lugs are possible, and one alternativeconfiguration is shown in FIGS. 2 and 3. In FIGS. 2 and 3 each part isgiven the same reference numeral as the corresponding part in FIG. I.

The lamp comprises an envelope 1] having a tapering portion 13 with awedge-shaped pressed pinch seal 14. Two leads 15 for the filament (notshown) extend through the closed end of the seal. The envelope ismounted in a cap 17 and seated in the cap 17 by two pairs of lugs 21, 22and 23, 24 respectively. The lugs are flat and have a complementarytaper to the taper of the seal 14.

The leads 15 pass through holes in the base 18 of the cap 17 and aresoldered or welded to the cap. The lead wires can be stiffened-up tomake this joint more sccure.

The caps shown in the drawings are bayonet caps; however it is clearthat other types of caps could be used, eg Edison screw caps, or 2 pincaps.

We claim:

1. An electric lamp comprising an envelope having a pinch seal at oneend thereof;

a pair of lead wires extending from the inside to the outside of saidenvelope,

at least one of said lead wires being sealed through and extendingbeyond said pinch seal,

a cap disposed about said pinch seal,

seating means including a plurality of lugs extending inwardly of saidcap and abutting said pinch seal to prevent rotational movement of saidenvelope, said at least one lead wire being fixedly attached near itsouter end to said cap to hold said seal against I said lugs and toprevent said envelope from moving axially relative to said cap.

2. A lamp as claimed in claim 1, wherein said pinch seal tapers on atleast one side from its centre towards at least one edge,

said cap has a closed end, and

said lugs comprise two pairs of lugs, the lugs of each pair being closertogether at their ends nearer the closed end of said cap.

3. A lamp as claimed in claim 1, wherein portions of said lugs have ashape complementary to the shape of said pinch seal whereby a face toface contact is maintained between said seal and said lug portions.

4. A lamp as claimed in claim I, wherein said lugs are formed by makingcuts in said cap and bending inwards the sections of said cap thusfreed.

5. An incandescent filament lamp comprising an envelope having awedge-shaped pinch seal at one end thereof, the thin end of the wedgebeing the end remote from the filament;

4 flat sides extending inwardly of said cap and abutting the sides ofsaid wedge shaped pinch seal to prevent rotational movement of saidenvelope, said lead wires being fixedly attached to said cap to holdsaid seal against said lugs and to prevent said envelope from movingaxially relative to said cap.

1. An electric lamp comprising an envelope having a pinch seal at oneend thereof; a pair of lead wires extending from the inside to theoutside of said envelope, at least one of said lead wires being sealedthrough and extending beyond said pinch seal, a cap disposed about saidpinch seal, seating means including a plurality of lugs extendinginwardly of said cap and abutting said pinch seal to prevent rotationalmovement of said envelope, said at least one lead wire being fixedlyattached near its outer end to said cap to hold said seal against saidlugs and to prevent said envelope from moving axially relative to saidcap.
 2. A lamp as claimed in claim 1, wherein said pinch seal tapers onat least one side from its centre towards at least one edge, said caphas a closed end, and said lugs comprise two pairs of lugs, the lugs ofeach pair being closer together at their ends nearer the closed end ofsaid cap.
 3. A lamp as claimed in claim 1, wherein portions of said lugshave a shape complementary to the shape of said pinch seal whereby aface to face contact is maintained between said seal and said lugportions.
 4. A lamp as claimed in claim 1, wherein said lugs are formedby making cuts in said cap and bending inwards the sections of said capthus freed.
 5. An incandescent filament lamp comprising an envelopehaving a wedge-shaped pinch seal at one end thereof, the thin end of thewedge being the end remote from the filament; a pair of lead wiressealed through said pinch seal in spaced apart relationship to oneanother and extending beyond said pinch seal, said lead wires beingconnected at their inner ends to said filament, a cap disposed aboutsaid pinch seal; seating structures including a plurality of lugs havingflat sides extending inwardly of said cap and abutting the sides of saidwedge shaped pinch seal to prevent rotational movement of said envelope,said lead wires being fixedly attached to said cap to hold said sealagainst said lugs and to prevent said envelope from moving axiallyrelative to said cap.